Preliminary checklist on species composition of small mammals and birds in Marine Research Excellence Centre (MAREC), Pulau Tuba.

Located in Langkawi archipelago, Andaman Sea, Pulau Tuba is one of the islands that is densely protected as a forest reserve. We investigated and documented the species composition of small mammals and birds at two different sites in the forest of UiTM Marine Research Excellence Centre (MAREC). Wire cage traps were used to capture non-volant small mammals while mist nets were used to capture bats and understorey birds. A total of 35 individuals were captured consisting of four species of small mammals and four species of birds. Among the most abundant species captured were Rattus tiomanicus, Leopoldamys sabanus and Cynopterus brachyotis. The calculated Shannon diversity index was 1.58 indicating a low diversity of small mammals and birds within the area. Our current study stipulated that few individuals were caught due to the rainy season affecting Pulau Tuba during the study period. Further surveys and studies should be conducted for a longer period in different seasons so that more species of fauna can be documented.


Background
Biodiversity is a required criterion to assess environmental changes and the sustainability of development activities.In order to compare the community structure of flora and animals across different ecosystem types and habitat management techniques, it is insightful to include the diversity of their distribution and pervasive nature [1].
Temperature, precipitation, soil composition, and local disturbances are some examples of variables that explain the variance in species composition, abundance, and interactions within different ecosystems [2] [3].Forests for instance are characterized by their dense vegetation and rich diversity that allow them to foster complex food webs and diverse niches that contribute to intricate relationship within the ecosystem [4].Islands, on the other hand, offer a distinctive natural environment due to their isolation and limited land area.Islands' restricted space and isolation can result in unusual speciation events, in which species change in response to the particular environmental factors unique to the island [5].
A wide variety of mammalian species have evolved on islands due to their isolated ecosystems and limited resources, and these species have adapted to the particular problems posed by their insular settings [6].Mammals that inhabit islands frequently experience astonishing adaptations as a result of the unique circumstances they come into contact with.Island mammals must effectively use their food sources due to their restricted space and resources, which frequently results in changes to their diet, behaviour, and appearance [7] [8].
As the island became isolated and having limited area, it also has given rise to a fascinating variety of small mammals and birds species that evolves in response to the challenges and chances they face.These small mammals, which range in species from shrews to rodents, have experienced astounding changes that provide insight into the processes of evolution, speciation, and ecological dynamics [9].Some animals, referred to as island dwarf species, have evolved to grow smaller than their counterparts on the mainland.This drive to insular dwarfism where small individuals living on isolated islands tends to evolve larger while bigger species shrink [10].On islands, there may be fewer resources and less competition, which may force these animals to adapt by becoming smaller in order to conserve energy 1316 (2024) 012009 IOP Publishing doi:10.1088/1755-1315/1316/1/012009 2 [11].
Having a critical role in the ecosystem, small mammals can be found nearly in every habitat ranging from terrestrial environments to lush forests, arid deserts and urban landscapes [12].Due to their roles as secondary consumers, these diminutive animals, typically distinguished by their modest size and fur-covered bodies have a significant impact on the plant ecosystem [13].Small mammals can be distinguished according to their differences in ability to move from one place to another, which is volant and non-volant [14].Volant small mammals refer to mammals that are capable of powered flight such as bats (order Chiroptera).This ability to fly is due to their wing which is an elongated arm and hand structures with a thin membrane of skin stretched between their fingers.Non-volant small mammals on the other hand are those small-sized mammals that lack the ability to fly.This includes rodents, insectivores and lagomorphs [15].
On the other hand, birds play a vital role in the ecosystems that they live in such as deep forests and oceans.They provide various services on the island ecosystem such as seed dispersal, pest control and pollination.On the island, due to their limited land areas, birds also often use the island as a crucial stopover point for them during their migration [16].Large bodies of water, such as lakes or oceans, are frequently crossed by birds on their migration routes.Along these routes, islands are positioned strategically to serve as rest stops.By jumping from one island to another, birds can break up their lengthy flights and save energy while avoiding the dangers of making continuous long-distance flights [17].
Located in Pulau Tuba, the 11 hectares UiTM Marine Research Centre serves as a focal point for environmental research and scientific study of marine ecosystems.Nestled within the captivating archipelago of Langkawi in Malaysia, this research centre functions as a beacon of knowledge, research, and conservation efforts focused on the intricate marine life and environments that surround the island.Although Pulau Tuba is considered a small island with an area of only 20 km 2 , it does not diminish the crucial role small islands play as a refueling station for migratory birds as well as the centre for species endemism [18].
In this study, we have examined the species composition and diversity of small mammals and birds by using different types of sampling methods.Since the study area's species composition and diversity are not yet documented, this survey would enhance future studies by providing information on the species lists for further conservation efforts.Given the area of our sampling site on the island, we found that it is important to document small mammals and birds from MAREC, Pulau Tuba.

Study area
The study was conducted at UiTM Marine Research Excellence Centre (MAREC) in Pulau Tuba, Malaysia (6.26603° N, 99.84522° E).The study area is a forest reserve that was established by UiTM Perlis branch acting as a research centre for numerous studies.The community around Pulau Tuba practices agriculture, tourism and water transport.On the inner part of the island, mangroves can be found acting as the house for various flora and fauna species.Two study sites were established with the first site being approximately 300 meters from the sea and the second site was approximately 100 meters from the sea (Figure 1).The two sites were chosen in order to observe the composition and diversity of small mammals and birds in an area that is closer to the sea as well as the area closer to the inner forest.Field sampling of small mammals and birds was conducted from 1 st October -4 th October 2022.

Data acquisition
Non-volant small mammals were caught using 20 collapsible cage traps (45x17x17 cm) placed on the ground at each study site with intervals of 10 meters apart from each other.The traps were left open for three nights and checked thrice daily at 0730, 1730 and 2330 hours.Oil palm seed was used as bait in the cage traps to lure the animals.Chiroptera was surveyed by using a total of three mist nets (12mx2mx36mm mesh) set up on each study site for three nights in a row.These nets were established at suitable locations and were checked twice between 2230 and 0700 hours.The mist was left open during the day to capture the understorey birds.
The captured individuals were safely secured in cloth bags (50g).For identification purposes, morphological measurement and live weight were recorded.Ear (E), hind foot (HF), tail (T), and head body (HB) were the measurements taken for small non-volant mammals.Meanwhile for bats, the measurement of forearms (FA), ears (E) and tails (T) were taken.As for birds, wing length, bill length, tarsus length, tail length, wing span and total body length were taken for identification.Any representatives of every caught species were photographed for documentation.After the data were recorded, all individuals were marked with non-toxic paint pen and immediately released at the edge of the forest.

Data analysis
The species composition and richness were calculated where the total number of species caught and the relative abundance were estimated by the total number of individuals per species divided by the total number of individuals.We also used the Shannon-Wiener Diversity Index (H') in order to estimate the species diversity in MAREC Pulau Tuba.This index is sensitive to changes in the abundance of rare species in the community.All the calculations were calculated using GraphPad Prism Simulator Version 9.

Species composition and abundance
This survey captured 35 individuals of small mammals and birds; represented by 30 individuals of small mammals from three families: Pteropodidae, Rhinolophidae and Muridae while the other five were birds from four families: Laniidae, Hirundinidae, Dicuridae and Stirigidae (Table 1).The most abundant non-volant small mammals were Malaysia wood rats (Rattus tiomanicus) with 15 captured individuals.Meanwhile, the most abundant species of volant small mammals were lesser short-nosed fruit bat (Cynopterus brachyotis) with seven captured individuals.Rattus tiomanicus has the highest relative abundance (43%), while the lowest relative abundance (3%) can be seen in Rhinolophus affinis, Hirundo tahitica, Dicrurus paradiseus, and Ninox sticulata.Shannon diversity index for this survey is 1.58 while evenness is 0.76.The Shannon diversity index (H') indicating that the diversity of small mammals and birds around the area is low.The higher the value of H, the higher the diversity of species in a particular community.The number of captured animals was relatively low due to the weather patterns.This study was conducted during the change of monsoon wind in which rain occurred in the afternoon and night.Since this island is near to Langkawi archipelago, it is expected to receive higher rainfall around September and October [19].Extreme precipitation could potentially impose multifaceted effects on organisms at the individual, population, and community levels as the availability of food supply, foraging behaviour, population growth rates, and competitive interactions could be greatly affected by it [20].Moreover, Bergallo and Magnusson (1999) stated that small mammals like rodents have higher reproduction rates during the rainy season [21].This indicates that the population of small mammals may be concentrating on reproductive activity at this time, which may result in fewer animals being captured.However, our study contradicted the findings by Kelly et al. (2012) which reported higher capture rates of small mammals observed following high rainfall [22].This stipulates that the abundance of small mammals was in accordance with regional populations as the number of individuals captured after rainfall was different within specific geographic locations.
We also found that the number of females was more abundant than the males in most species captured.This study was in line with [23] which reported the high number of females during the wet season.This is due to the reproductive rates being higher during the rainy season in both sexes of small mammals as it is related to the polygyny behaviour in small mammals [24].In polygyny, a male seeks many females to increase reproductive success during the rainy season causing more females to be present.The sex ratio is likely biased towards females since females are more likely to travel farther than males do, increasing their risk of getting trapped.This leads to seasonal reproduction which causes newborn recruitment to peak near the end of the breeding season and results in a surge in the number of juveniles [23].A study by [25] reported that the neuroendocrine mechanisms affect how birds and mammals regulate their seasonal reproductive cycles.It underlined the regulation of thyroid hormone catabolism by thyroid-stimulating hormone (TSH) in the mediobasal hypothalamus which is important for seasonal reproduction.

Cynopterus brachyotis (Lesser short-nosed fruit bat)
A total of seven individuals were captured from sites.This species is common in Southeast Asia, including Malaysia, and is a member of the Pteropodidae family.It is a generalist and eurytopic species that can be found in a variety of habitats, encompassing urban areas, secondary forests, dipterocarp forests, gardens, mangroves, and strand vegetation, though it is most usually found in disrupted and fragmented areas [26].From its common name, this species has a key distinguishing feature that differs from other bats which is their shirt, and blunt nose which is different from the long, pointed nose of other bat species.The species has a body length of about 10-15 cm and a wingspan of about 30-40 cm [27].Mist-netting successfully sampled this species of bats due to their inability to detect solid objects in their flyway making them the most abundant volant small mammals being caught.

Rhinolophus affinis (Horseshoe bat)
There was one individual captured from site B. With most prominent feature of their unique noseleaf which is shaped like a horseshoe of a leaf that is located on their noses, this species of bat is highly specialized in echolocation [28].This feature allows them to find prey (typically insects) and navigate in total darkness, as well as avoiding obstacles.The high-frequency sounds that they emit, often beyond the range of human hearing will propagate and bounce off objects in the environment.The returning sound waves that are detectable by their highly sensitive ears will be processed making them very good hunters with highly precise prey locations [29].Since the mist nets are used in this survey, this species is unlikely to be sampled due to their ability to avoid solid objects in their way.

Rattus tiomanicus (Malaysia wood rat)
This species was found to be the most abundant with a total of 15 individuals captured at both sites.This species is native to Southeast Asia and can be found in countries such as Malaysia, Thailand and Singapore.This nocturnal rodent is a medium-sized rat that has a body length ranging from 15cm to 25cm weighing around 100-200 grams [30].In Southeast Asia, this rat is considerable as economic and public health, as a pest and carrier of infectious pathogens [31].It is a definitive host to some of the nematode parasites namely Angiostrongylus malaysiensis [32] and A, cantonensis [33] among others.

Leopoldamys sabbanus (Long-tailed giant rat)
There was a total of seven captured individuals at both study sites being caught in collapsible cages.Since this species is native to Southeast Asia, it has been recorded to be found in Malaysia, Thailand and Philippines.Their body length is around 18cm to 22cm with the weight around 200-410 grams [34].This species can be identified by the unique structure of its long tail.The long tail, which is prehensile, helps with the locomotion to move from one area to another.The tail is used for grasping and climbing making them reach a higher area to forage [35].The location of Pulau Tuba is around the Langkawi archipelago.A study by Lit et al., (2011) found that 35 of Leopoldamys sabbanus were caught at Lubuk Semilang, Pulau Langkawi [36].However, it is interesting to note that this species was not found in the studies conducted on islands such as Pulau Perhentian, Pulau Pangkor and Pulau Bidong which are mainly located on the east coast [37].

Lanius cristatus (Brown shrike)
A total of two individuals were captured during this study at both sampling sites.The East Asian-Australasian Flyway is home to the brown shrike (Lanius cristatus), a long-distance migrating passerine bird.This indicates that they are travelling in extensive distances during seasonal migrations making them a highly migratory bird [38].The four subspecies that make up this species breed in eastern Eurasia and often spend the winter in Southeast Asia.According to the IUCN Red List, the species is not currently regarded as being in the "Vulnerable" category [39].The Brown Shrike is famous for its predatory tendencies and may prey on tiny birds.In Malaysia, there have been reports of brown shrikes attempting to attack munias with white rump [40].

Hirundo tahitica (Pacific swallow)
Only one individual was trapped during this survey at the sampling sites.The Hirundinidae bird family includes the Pacific swallow (Hirundo tahitica), commonly referred to as the Pacific martin.It is native to the Pacific area, which contains Tahiti, Fiji, and Samoa, among other islands while also migrated across Southeast Asia [41].Even with their ability to migrate, there are still understudy on their migratory behavior and patterns.The Pacific swallow is a little bird, with a length of only 13 to 15 cm.It has a long, pointed tail, long, slender wings, and a thin body.The bird's underparts are white, while its upper parts have a glossy blue-black colour.It has a white throat and breast, as well as a dark blueblack cap on its head that reaches down to cover its eyes [42].

Dicrurus paradiseus (Greater racket-tailed drongo)
There was one individual found during the study.A medium-sized passerine bird, the Greater Rackettailed Drongo (Dicrurus paradiseus) can be found throughout Asia, including the Indian subcontinent, Southeast Asia, and portions of China.It is recognised for having a long, forked tail with outer feathers that are elongated and resemble rackets or streamers [43].The species is well-renowned for its vocalisations, which include various calls and imitations of different bird species.It frequently occupies a prominent perch in a tree and uses its vocal prowess to protect its territory and fool other birds [44].

Ninox sticulata (Brown boobook)
Being the only nocturnal bird that was found during this study, Ninox sticulata also known as brown boobook is a native species to a wide geographic range including South Asia, Southeast Asia and Indonesian archipelago.They have a spherical face disc with a characteristic white "V" shape between their eyes, giving them a distinctive appearance.They are between 25 and 36 cm long.The underparts are white with brown streaks while the upperparts are brown with white markings [45].This owl is known for their unique and distinctive calls and vocalizations behavior.Their sounds include a series of whistling, hoots and screeching that vary in pitch and tone [46].

Conclusion
This short survey managed to document a total of eight different species (four species of small mammals and four species of birds) at Marine Research Excellence Centre (MAREC), Pulau Tuba.This indicates that there is still an opportunity to survey and record the forest fauna of Pulau Tuba particularly small mammal diversity in the future.Different sampling methods and baits should also be used to increase the frequency of small mammals being trapped.Therefore, it is crucial to conduct more research and studies in this area to document the fauna diversity which could facilitate the conservation effort on this island.

3 Figure 1 .
Figure 1.Study area at MAREC, Pulau Tuba shows Site 1 (300 m from the sea) and Site 2 (150 m from the sea) of the study area (numbered box).

Table 1 .
Small mammals and bird species captured during the study period.

Table 2 :
Summary of the index calculations.